In a competitive examination, the average marks obtained was $45 .$ It was later discovered that there was some error in computerization and the marks of $90$ candidates had to be changed from $80$ to $50$ , and the average came down to $40$ marks. The total number of candidates appeared in the examination is
$520$
$550$
$540$
$525$
The average age of students of a class is $15.8$ $years.$ The average age of boys in the class is $16.4\, years$ and that of the girls is $15.4 \,years.$ The ratio of the number of boys to the number of girls in the class is
The average age of a committee of $8$ members is $40 \,years.$ A member, aged $55\, years,$ retired and he was replaced by a member aged $39\, years.$ The average age of the present committee is (in $years$)
Roshan bought $5$ pants at $Rs.\, 25$ each, $10$ shirts at $Rs.\, 50$ each and $15$ ties at $Rs.\, 35$ each. Find the average price of all the articles in $Rs.$
Average weight of $3 \,cm$ men $A , B , C$ is $84 \,kg$. Another man $D$ joins the group and the average now becomes $80 \,kg$. If another man $E$ whose weight is $3 \,kg$ more than that of $D$ replaces $A$ then the averageweight of $B , C , D$ and $E$ becomes $79\, kg .$ The weight of $A$ in $kg$ is
The average age of $5$ sisters is $20 \,year.$ If the age of the youngest sister be $4 \,year,$ what was the average age of the group of sisters at the birth of the youngest sister in $year$ ?